Evaluating and grading meat animals, both live and slaughtered, have been historically performed by humans. Because of this it is very difficult to achieve accuracy, efficiency and consistency. Both producers and packers demand an objective means of classifying their animals accurately according to their carcass real values. However, since an accurate, quick, and consistent grading system has not been put into place, producers are not being paid for the true value of their animals. Currently, producers are paid on an average basis. The price differential between a high-yield and a low-yield grade is less than it should be. Therefore, it is important to the meat industries that improved or new technologies must be developed in their evaluation systems in order to be able to accurately measure the animal or carcass characteristics that are of significant value.
Typically, ultrasonic images of the Longissimus dorsi (rib eye muscle in beef and loin eye muscle in hogs) have been used to evaluate livestock. This has been done by positioning a linear transducer (scan line is in the same direction as the linear transducer) in either a perpendicular or parallel direction with respect to the backbone of the livestock. Previously, many types of positioning apparatus have been implemented for consistently positioning a transducer in a transverse (perpendicular) position along the backbone of an animal or carcass. For example, see U.S. Pat. Nos. 4,785,817; 4,099,420; 3,603,303; and 3,496,764 each granted to James R. Stouffer, one of the coinventors of the present invention. As shown in the sales catalog for ITHACO's SCANOGRAM, a guide-cam set Type C was available for linear scans consisting of a series of individual scans in a linear direction.
EPO Patent application publication number 0 337 661 A1, entitled, "Method and apparatus for grading of live animals and animal carcasses" teaches method and apparatus for longitudinal (parallel to the backbone) scanning and image recognition to determine automatically fat and muscle characteristics. Wilson was not the first to use longitudinal scanning to evaluate carcasses, as shown by the Phd thesis by Wayne A. Gillis entitled "An Evaluation of Indices of Carcass Yield, Physical Composition and Chemical Composition in Swine; and Ultrasonic Measurement of the Longissimus Dorsi Area and Fat Thickness in Beef and Swine", which shows longitudinal scanning. Another group currently using longitudinal scanning is CSB-SYSTEM of America Corporation.
Neither Wilson, Gillis or CSB teach some of the problems associated with performing longitudinal scans or method or apparatus for consistently locating the transducer on the animal or carcass. One problem with longitudinal scanning occurs when the transducer is parallel to the back fat layers. Artifacts or multiples of the fat layers and the muscle/fat interface show up in the image of the muscle layer. These multiples occur as a result of the sound waves rebounding directly back off of these layers and interfere with image recognition apparatus methods for determining muscle and fat composition. As can be seen by the advertising literature, the CSB system has the problem of artifacts as shown in the ultrasound image displayed on the first page.
These problems were solved by the methods and apparatus for positioning an ultrasonic transducer for longitudinal scanning of an animal or carcass taught in U.S. Pat. No. 5,316,003 granted on May 31, 1994. This system comprises positioning the transducer such that it is not parallel to the rib line, thus eliminating artifacts. Although, this system greatly improved scan quality and reliability for commercial use, further improvements needed to be made.
Like all the other systems known to be in use at this time, the positioning device shown in U.S. Pat. No. 5,316,003 requires the user to first position the transducer on the animal or carcass and then look away from the transducer to check the image on a display screen separate from the transducer (See FIG. 1 of U.S. Pat. No. 5,316,003). Even this slight turning by the user was sometimes enough to jar the transducer. An experienced user would quickly realize that proper positioning or contact had been lost when looking at the display. However, the line speeds in a packing plant require an operator to evaluate one carcass every three seconds. Therefore, there is little time to reposition a transducer. Furthermore, a system for use in a commercial setting must be capable of producing reliable data regardless of the experience level of the operator.
The present invention includes the discovery of the problems described herein and their solutions.